Striking mechanism.



P. M. OBER. STRIKING MEGHANISM.

UNITED sTATEs PATENT oEEioE.

FRED M. BER, OF MORRISVILLE, VERMONT.

STRIKING MECI-IANISM.

To all whom it may concern Be it known that I, FRED M. OBER, a citi- Zen of the United States, residing at Morrisville, in the county of Lamoille and State of Vermont, have invented a new and useful Improvement in Striking Mechanism, of which the following is a specification, accompanied by drawings, forming a part of the same.

My invention relates to that class of mechanisms which are embodied in stone working and other tools, comprising means for imparting ak blow intermittently to a cutting or other tool.

It has for its object to simplify the construction, and increasel the durability and efficiency of this class of mechanisms. I accomplish these objects, among others, by the construction and arrai gement of parts as hereinafter described, the novel features being pointed out in the annexed claims.

Referring to the accompanying drawings, Figure 1 is an elevation of a tool embodying my invention. Fig. 2 is a central longitudinal sectional view. Fig. 3 is a detached side View of the stationary cam plate. Fig. 4 is a detached side View of the rotatable cani plate. Fig. 5 is a view of the under side of the stationary cam plate. Fig. 6 is a View of the top side of the rotatable cam plate.

Similar reference figures refer to similar parts in the different views.

Referring to the accompanying drawings, 1 denotes a cylindrical casing having a transverse partition 2 and provided at its upper end with an internal screwthread 3 to receive the end casing 4 of a flexible shaft of any suitable construction by which the rotative parts of the mechanism is connected with a motor. In the present instance the fiexible shaft comprises a series of links the end link 5 engaging an eye 6 in the end of a rotatable spindle 7. The cylindrical casing 1 is provided at its lower end with an internal screwthread 8 to receive a screwthreaded washer 9, and also the upper end of a tubular handle. The tubular handle 10 incloses a cylindrical chamber 11 and at its lower end it is provided with a passage 12 of less diameter in which is loosely inserted a shank 13 of a cutting or other tool 14:. rIhe rotating spindle 7 extends through the washer 9 into the cylindrical chamber 11, and is provided at its lower end with a screwthread 15 upon which is held a head or hammer 16 nearly lling the cylindrical Specification of Letters Patent.

Application led January 16, 1913.

Patented June 16, 1914.

senai No. 743,367.

chamber 11. The screw threaded washer 9 bears against a'shoulder 17 in the casing 1, and between the washer 9 and the hammer 16 I insert a spiral spring 18 having its opposite ends bearing upon loose washers .19 and 20. The spindle` 7 is provided near ltslupper end with a screwthread 21 upon which is screwed the rotatable cam plate 22, which is normally held against the upper surface of the washer 9 by the tension of the spiral spring 18.

The casing l incloses a cylindrical chamber 28 which contains the rotatable cam plate 22 and is provided with an interior screwthread 24E which is engaged by a screw threaded stationary cam plate 25 which is screwed firmly against the transverse partition 2. The stationary cam plate 25 is provided on its under surface with triangular projections 26, in the present instance three in number, their surfaces forming cams adapted to Contact with similar triangular projections 27 on the lower or rotatable cam plate 22, in the present instance two in number. In the normal position of the parts, a tree space exists between the opposing cam surfaces of the projections 26 and 27, allowing the cam plate 22 to rotate freely without being brought into contact with the cam plate 25.

In order to render the mechanism opera tive the shank 13 of the tool is inserted in the passage 12, with its upper end 28 against the hammer 16, with the lower end of the tool against the work to be operated upon. If the handle 10 is then forced downward with a. slight pressure suiiicient to compress the spring 18 the rotating spindle 7 will be forced upward carrying the cam plate 22 until the triangular projections 26 extend into the path of the projections 27, causing the tips of the latter to successively contact with the tips ofthe projections 26 as the spindle rotates. A series of blows or downward impulses will therefore be given to the spindle 7 and impart it through the hammer 16 to the tool 14. If the extreme tips only of the projections 26 and 27 contact, light impulses will be given to the cutting tool 14, and these blows or impulses will be in creased in force accordingly as downward pressure upon the handle 10 is increased. The pressure upon the handle 10 controls with nicety the force imparted to the cut ting tool, and a release of pressure upon the handle 10 allows the spiral spring 18 to immediately depress the rotating spindle and render the cams inoperative. The actuating cam plates 22 and 25 are both held concentrically with the spindle 7, and the spindle 7 is in' direct alineinent with the shank 13 of the cutting tool, so that the force imparted by the blows is directed in lines parallel with the axis of the cutting tool.

In the operation of the mechanism the cam plate 25 constitutes the driving cam by which the blows or impulses are imparted to the driven cam plate 22. By making the cam plate 25 stationary, and the cam plate 22 rotatable, I obviate the necessity of providing ball. bearings or antitriction devices to receive the end thrust of the rotating spindle, for the reason that the cam plate 22, while being actuated by the cam plate 25, is raised entirely free from its bearing upon the washer 9. rI`he cost of construction is thereby largely decreased and the durability of the instrument increased. The operating mechanism is wholly in control of the attendant as well as the force of the blows imparted to the cutting tool, the latter depending entirely upon the amount of downward pressure exerted upon the handle 1G.

Y rIhe construction described above is especially adapted to impart comparatively moderate blows of varying torce which are within the control of the operator. In order to further increase the force of the blow when required as, for example, when the apparatus is employed for driving nails, or other purposes, I interpose a spring 29 between the lower end of the hammer 16 and the lower, or end, wall of the cylindrical recess 11, said spring 29 being stronger than the spring 18 and of'suitable length to raise the hammer far enough, when the spring 29 is expanded to bring the cam surfaces 26 and 27 toward each other and relieve the pressure of the cam 22 on the fixed washer 9. In operation, a slight upward movement of the hammer 16 and spindle 7, by the pressure of the tool against the hammer, will bring the cams into operative contact and cause the hammer to be forced violently against the spring 29. The movement of the hammer will slightly compress th-e spring k29, thereby checking the upward impulse which would otherwise be imparted to the casing by the stroke oit' the cam against the resistance of the tool. At the completion of the stroke, the recoil of the spring 29 will again restore the normal relation of the cams to each other.V `Washers 30 and 31 are preferably interposed between the ends of the spring 29 and the end wall of the recess 11 and the hammer 16.

I claim,

1. In an apparatus of the kind specified, a casing, a rotatable spindle journaled concentrically in said casing and capable of a longitudinal movement therein., a spiing applied to force said spindle in one direction, an annular cam plate held in a fixed position in said casing and concentrically with said spindle, and a cam plate carried by said spindle normally spaced from said fixed cam plate by said spring.

2. In an apparatus oi the kind specified, a rotatable spindle carrying a hammer for contacting with the tool and capable ot a longitudinal movement, a stationary cam arranged radially to said spindle, a radial cam carried by said spindle and opposing said stationary cam, yielding means applied to said spindle to normally hold said cams apart, and means to impart a rotary motion to said spindle.

3. In an apparatus of the kind specified, a rotatable spindle, a hammer carried by one end of said spindle adapted to strike a tool held in alinement, a spring tor fore ing said spindle endwise toward the tool, and opposing actuating cams lor :forcing said Aspindle in the same direction as said spring, said cams being maintained normally inoperative by the tension of said spring.

4. In an apparatus ot the kind specified, a casing, a spindle journaled therein and capable of a limited longitudinal movement, yielding means for holding said spindle in its normal position, a fixed cam held in the casing, a rotatable cam carried by said spindle and normally spaced from said fixed cam and a passage in said casing to receive a tool in alinement with said spindle, and means for rotating said spindle.

5. In an appa 1atus of the kind specified, a casing, a rotatable spindle journaled therein and capable of a slight longitudinal movement, a stationary cam held in the easing and in axial alinement with said spindle, a cam carried by said spindle, a spring with its tension applied to space said cams and normally hold said spindle in its normal position, said casing having a passage for the admission of a tool to move said spindle endwise and bring said cams into operative relation to each other.

6. In an apparatus of the kind specified, a easing having a transverse partition, a stationary annular cam plate held against said partition, a rotatable spindle extending through said partition and said annular cam plate and capable of a slight endwise movement, means ior rotating said spindle, a cam plate attached to said spindle, and opposing said stationary cam plate, a spring applied to said spindle to sepa ate said cam plates, means for limiting the endwise movement oi said spindle, said casing having a passage to admit a tool in position to exert a pres` sure to compress said spring and bring said rotatable cam into operative position.

7. In an apparatus of the kind specified, a

tubular casing having a transverse partition integral therewith, a second transverse partition, a rotatable spindle passing through both of said transverse partitions, a tixed cam plate held against said integral partition, a cam plate att-ached to said spindle, a spring applied to said spindle to move it endvvise and hold its attached cam plate in inoperative relation to said Xed cam plate, a passage in said casing for the reception of a tool in alinement with one end of said spindle, and means applied to the opposite end of said spindle to rotate the spindle and its attached cam plate.

8. In an apparatus of the kind specified, a casing having a rotatable spindle journaled therein, opposing cams supported by said casing and said spindle respectively and arranged concentrically With the aXis of said spindle, a hammer face on the end of said spindle, and yielding means for normally separating said cams.

9. In an apparatus of the kind specied, a rotatable spindle, a casing having bearings for said spindle, a cam carried concentrically by said spindle, a fixed cam held by said casingl concentrically with said spindle, a spring applied to said spindle to hold said cams separated, a second spring applied to said spindle in opposition to the tension of said irst spring, said second spring being stronger than said first spring.

10. In an apparatus of the kind specified, a casing having a socket for a cutting tool, a spindle journaled in said casing, a iiXed cam held by said casing, a rotatable opposing cam held by said spindle, a spring applied to said spindle to move it toward the cutting tool and normally to space said cams, and a second spring applied to said spindle in opposition to said rst mentioned spring.

FRED M. OBER. Witnesses:

B. J. KELLEY, I-I. WAITE.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patenti, Washington, D. C. 

